To PCV or NOT to PCV

This is a 'bone' question...

Do TD4's have a 'real' PCV system or just a crankcase 'filter' and where does the 'system' join the inlet before or after the turbo...

Just watched a video on 'The Tube of You' and it stated that turbo'd diesels don't have PCV systems................................................................................................................................................................................................................................................@@@@@(Tumbleweed)..........................................................................................@@@@@@@(more Tumbleweed)..........................................................................

'Go get the 'Nodge'..'

'The Nodge is asleep.......'

'Well, GO WAKE HIM UP!!!'

Yes TD4 has a PCV filter system you can go with the original or change to the BMW filter less one personally I prefer the filter original system and change it every year or two depending if you use the car on long or just short journeys.

If your PCV filter is blocked up then you can say 100% that your manifold & EGR will be also, if it as not been cleaned since new, I think most have cleaned there manifold by now & changed PCV

Yep, Done all that and I have just watched the video again and it does say that a 'filter system' is used on 'some diesels' and that the filters need to be changed on a 'regular basis' just threw me a bit as I was expecting a 'I know all this' feeling then heard the 'contradiction' of what I knew/know/thought I know...Seems turbo'd diesel PVC systems are different from petrol in how/where they connect to the inlet or something(I am going to have to watch the video again 'as I is a bit thick'......) No doubt when 'Nodge' wakes up he will post the definitive PCV post of all time for all to see......Then we will 'know stuff'....(or think we will, anyway....) B-S

a history lesson :
https://en.wikipedia.org/wiki/Crankcase_ventilation_system

edit-delete: as correct td4 system info in post '6'
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hd3 said:

a history lesson :
https://en.wikipedia.org/wiki/Crankcase_ventilation_system

edited to add : a.f.a.i.k. .. on the td4 / m47r .. the system vents
back into the air intake post air-filter / maf sensor .. pre turbo
'cause if it were before the air-filter and maf sensor the gases and oil vapour would contaminate both
and .. if it were vented back in post turbo .. the turbo pressure would cause an issue ..

on 2 old V8's i owned ( late 60' models ) the vent simply ended inside
the air filter housing ..

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Click to expand...

Cheers, the more knowledge the better...Ta!!

The M47R uses a standard BMW Positive Crankcase Valve and filter system, common to pretty much all BMW diesels. This system works by allowing the crankcase to naturally develop small positive pressure, in other words there is a small pressure in the crankcase all the time the engine is running. How much pressure is governed by the current boost pressure. There are also two types of crankcase filter, as we know. There is only one type over PC Valve however.
If you look at the PCV/filter assembly from the front, the there is a primary vortex filter is on the right of the housing. The left side of the housing contains the loo roll fluffy filter or later secondary vortex filter. The Valve is part of the housing cover, contained in the raised section of the lid between the primary vortex and fluffy/ secondary vortex. From here the gasses are directly vented into the inlet manifold, which forms part of the cam cover assembly . The PC Valve is only fully open when the engine is off boost and when the crankcase is under a pre-set level, this being controlled by a light spring. Under boost conditions that exceed the normal crankcase pressure, the valve closes off to prevent unreasonably high crankcase pressure. As boost drops, so the valve opens, allowing the crankcase to vent into the inlet manifold to be burned.
It's normal practice to have a vent onto some part of the intake system that is at normal atmospheric pressure, which is into the turbo feed on the M47.

There are stories of turbo seals failing because the PCV filter is blocked, but I can't see how that can happen myself. The turbo is not connected to the crankcase, except at its oil return point. Imho if the turbo seal fails, then it's either coincidence or is a sign that maintenance has been lacking hence the blocked filter in the PCV in the first place.

I personally prefer to use the fluffy cotton wool filter. Looking at the state of the filter after 12 months/ 8K miles, then loads of oil gets past the primary vortex. So my way of thinking says loads will also get past a secondary vortex. This is why I prefer to use the simple but effective fluffy filter.

Nodge68 said:

I personally prefer to use the fluffy cotton wool filter. Looking at the state of the filter after 12 months/ 8K miles, then loads of oil gets past the primary vortex. So my way of thinking says loads will also get past a secondary vortex. This is why I prefer to use the simple but effective fluffy filter.

Click to expand...

When I got my 05 td4 it was p*ssiing oil from every orifice. I did the EGR mod and - more importantly - changed the fluffy filter. After a few weeks the car was completey drip free as all the oil leaks stopped.
Now - the interesting thing - if I let it idle with the oil filler cap loose it would rattle for a few seconds then stick down as a litle vacuum pulled it down. I subsequently changed for a BMW Cyclone type one and now on idle a loose cap continues to just rattle and never sticks down on vacuum. So I deduce the fluffy flter arrangement with a mint condition filter may be the best crankcase ventilation system - BUT - my oil leaks have not returned so I am a happy bunny

Nodge68 said:

I personally prefer to use the fluffy cotton wool filter. Looking at the state of the filter after 12 months/ 8K miles, then loads of oil gets past the primary vortex. So my way of thinking says loads will also get past a secondary vortex. This is why I prefer to use the simple but effective fluffy filter.

Click to expand...

Cheers Nodge, It does all make sense.. When I serviced my PCV to 'upgrade' it to the BMW vortex system I found it had already been done. Swapped it out anyway as the PCV assembly bolts had been 'ragged'. I am sceptical of the effectiveness in the long term of the vortex system and will probably go back to the 'bog roll' filter(I have a couple of new ones anyway) as I do like to 'service' stuff....The 'Non service items on cars have a finite life in my book. Interesting stuff...if you are like me....a bit of a spotter.

Just watched the video again and it actually means complete sense and I must have been 'Monging' it (no offence to any 'Mongs' out there BTW). The 'poster' mentioned the filter system and it's 'failings' if NOT SERVICED REGULARLY. Just got thrown by what he stated at the start of the video. Thanks everyone!!

Check the video out..